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A Cal Fire investigator examines debris on July, 8, 2025 from the July 1 explosion and fire at a fireworks storage facility in Esparto in Yolo County. Seven people were killed. (Photo courtesy Cal Fire via Bay City News)

Seven people – including an optician with San Ramon Valley ties and a Northern California sheriff’s lieutenant – have been arrested in connection with an explosion at an illegal fireworks facility in rural Yolo County that killed seven last July. 

The massive series of explosions at the farm near Esparto leveled buildings and storage structures and ignited a 78-acre fire in an agricultural area about 40 miles northwest of Sacramento. 

On Friday (April 10), Yolo County District Attorney’s Office officials announced murder charges for five people, along with conspiracy charges for those five plus two others allegedly involved in an illegal fireworks storage and wholesale operations known as Devastating Pyrotechnics, Devastating Pyro Displays and BlackStar Fireworks. 

The businesses used property on a farm owned by Yolo County Sheriff’s Office Lt. Samuel Machado and his wife Tammy, who also worked for the sheriff’s office. 

Facing seven counts of murder are Samuel Machado, Kenneth Kin Chee, Gary Chan Jr., Jack Lee and Douglas Michael Tollefsen.  

The San Francisco Chronicle first reported last year that Chee, 48, was an optician at Costco who lived in San Ramon and previously resided in San Francisco. He was arrested while at Disney World Resort in Florida last week, according to KCRA.

Kenneth Kin Chee. (Photo courtesy Orange County, Fla., Sheriff’s Office)

They are also facing charges of conspiracy to possess explosive devices, possession of explosives and transportation of explosives, among other things, along with Craig Allen Cutright and Ronald John Botelho III, according to an indictment filed on April 3 in Yolo County Superior Court. 

In a separate filing, Tammy Machado is facing charges of mortgage fraud, filing false tax returns, animal cruelty and child endangerment. 

Samuel Machado is also facing charges of child endangerment, animal cruelty, tax fraud and illegal possession of assault weapons. 

Last month, a scathing civil grand jury report found that the illegal fireworks business had been operating for years at the Machado property with the full knowledge of nearly a dozen county employees and political leaders, who fostered an atmosphere of permissiveness with regards to how the county oversees farmers and their land. 

“Although numerous local officials, including Sheriff’s deputies, fire officials, officials in the County building, code enforcement, planning and County Counsel’s office, all knew about the fireworks businesses, none of them took any action,” according to the report. 

The report goes on to say it’s possible that the county looked the other way, in part, because it was reluctant “to antagonize some sheriff’s officials by initiating an enforcement action on property owned by sheriff’s department employees”.

It also found that while the Yolo County Board of Supervisors paid lip service to the need for reforms, there is currently no evidence that it has initiated any sort of thorough or systematic review of county processes or procedures.

The victims who died in the explosion were identified as Neil Justin Li, 41, of San Francisco; Christopher Goltiao Bocog, 45, of San Francisco; Jesus Manaces Ramos, 18, of San Pablo; Jhony Ernesto Ramos, 22, of San Pablo; Angel Mathew Voller, 18, of Stockton; Carlos Javier Rodriguez-Mora, 43, of San Andreas; and Joel Jeremias Melendez, 28, of Sacramento.

Editor’s note: Story by Kiley Russell of Bay City News Service. DanvilleSanRamon.com editorial director Jeremy Walsh added local details.

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